Wall plug



July 21, 1925. 1,546,736

F. W. KRAUSE WALL PLUG Filed Dec. 29, 1924 JMJIW JMJML 1mm J/MMU 3 Patented July 21, 1925.

UNITED STATES v 1,546,736 PATENT OFFICE.

FRIEDRICH WALTER KRAUSE, OF AI/IONA, GERMANY, ASSIGNOR TO JOHN FERREOTJ MONNOT, OF MILL HILL, LONDON, ENGLAND.

WALL PLUG.

Application filed December 29, 1924. Serial No. 758,557.

To all whom it may concern:

Be it known that I, FRIEDRICH WALTER KnAUsE, a German citizen, residing at Altona, Germany, have invented certain new and useful Improvementsin or Relat ing to Wall Plugs, of which the following is a specification.

This invention relates to wall plugs of the type in which there is employed a fibrous or other material of a yielding or flexible nature which is easily subject to compression and expansion.

It is known that for the purpose of inserting plugs, or forming a suitable support, loose fibrous material, for instance cotton wool, is packed into the hole in the wall.

It has'been attempted to reduce the difliculties involved in such packing by forming the loose fibrous material into lightly glued,-

yielding or braided sockets, but although these fibrous material sockets are more easy to insert than loose fibrous material, their holding power is smaller and less reliable.

When using loose fibrous material it is forced into the hole in the wall until it is full. The fibrous material sockets have on the other hand the disadvantage that, owing to their lack of strength, they cannot be forcibly driven into the hole in the wall, but only introduced into itwith a slight clearance. Consequently the quantity of fibrous material introduced when using them is less than when loose fibrous material is used.

When a socket is used it grips only by the radial spreading out of the socket which oc-' curs when it is driven in by the screw or the like. The amount of such spreading out always depends therefore on the diameter of the screw or nail. If the hole in the wall is even a trifle larger than the minimum diameter required to enable the socket to be introduced, the holding power of the socket will soon disappear.

In order to overcome the disadvantages above referred to there is employed in accordance with the present invention a wall plug comprising a filling material of the kind hereinafter referred to, such as a soft fibrous substance or the like, held between and stiffened by bars, wires, or the like connected together by a transverse .portion at one end so as to form a stem-holdfor the filling material and open at the other end, the bars or Wires being provided with retaining means such as fingers and/or a holding collar, whereby the plug can be forcibly dr1ven into a small hole in a wall or other member, the fibrous material of the plug being at the same time compressed, before the screw or nail to be inserted is driven in. By this means a maximum quantity of fibrous material can be stiffened and held together without prejudicially affecting the degree of resiliency necessary for the material.

For the filling mass, there must be used a material such as a fibrous material, for example cellulose or asbestos, which can be compressed from along thin cylinder to a short and thick one accompanied by a yielding in the axial direction and expansion in the radial direction, and which will penetrate flexibly and adapt itself to any shape of hole and fill up all the corners of the rough holes in the wall, and which when the compression continues, develops a uniformly distributed, elastically increasing, exceedingly powerful pressure, and remains under pressure and properly transmits this frictional pressure between the nailor the like and the walls of the hole.

The necessary property that must be possessed by the filling material, namely that its denslty must be capable of being in? creased by pressure and that it must maintain the degree of increased density under pressure, cannot be obtained by the use of power than a fibrous material socket loosely introduced into the same hole. Even if the fibrous material stiffened in the manner above mentioned were introduced with the same clearance as the socket, it would still have a greater holding power than the lat- 105 ter, as owing to the use of the stiffening bars, the space between which is wholly filled with the fibrous material in place of a socket, there is available material for filling the hollow space between the plug, and the ill) wall of the hole. In this way, larger variations in the admissible diameter'of the hole become permissible, the safety and reliability of the plugs are accordingly increased, and, owing to the distribution of the pressures in the body of fibrous material which is clamped by the stiffening bars, the soft front plaster portions of the walls are relieved from strain, so that breaking off of such portions is avoided.

It is immaterial for their action in the case of the present wall plugs whether the fibrous material mass is held and stiffened inside or outside its circumference by one or more straight or bent bars,wires or the like. In the former case the stiffening members are arranged within the body of the fibrous material near the outer surface thereof so that in this case also the greater portion of the fibrous material is clamped by the stiffening bars or wires.

The cost of the stiffening bars is quite small, as they can be made from waste sheet metal, and at the same time the cost involved in the special shaping of sockets is eliminated.

With wall plugs according to the present invention the holding power is considerably increased as compared with that of the ordinary known fibrous material sockets, whilst their safety and reliability is also greatly improved. When employing the improved wall plugs it is only necessary to make a very small bore hole in the material into which the plug is to be inserted, whilst at the same time the plugs have a very strong holding power, so that the present plugs present an advantage over other types of plug in this respect.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described'more fully with reference to the accompanying drawings, in which I Figure 1 illustrates a wall plug in side elevation before the stemming or compression of the'fibrous material therein.

Figure 2 shows the same wall plug viewed at an angle to Fig. 1 and in the hole of a wall, in section, after wedging it in.

Figure 3 also shows the same wall plug as in Figure 1 in side elevation but with a nail driven in and in the condition it assumes in the wedged-in position.

Figure 4 represents awall plug similar to that shown in Figure 1 but of a construction modified so as to assist a dove-tail-like spreading out of the strengthening bars.

Figure 5 represents the wall plug, shown in Figure 4, but in the condition it assumes in the wedged-in position.

Figure 6 is a detail view of a covering cap for the plug, and

Figure 7 a plug provided with a covering cap slmilar to that shown in Figure 6.

1,54a,7sa

Referring to Figure 1, a is the fibrous material insertion which is pressed in between the stiffening bars b arranged outside the said material. These bars are bent into a U shape at 0 and formed into fingers at d at which point is located a holding collar la.

In Figure 2, e is the deep hole in the portion of wall 7 shown in section. By striking against the end d of the bars, the plug is first driven into the wall until the collar is rests against the face of the wall. In driving a nail or a screw into the fibrous material a, the latter is compressed in the axial direction between the bars I) and forcibly stemmed at the end 0 of the plug. The fibrous material then overflows laterally from thebars and presses firmly, with production of a frictional pressure, against the walls of the hole, the bars I) being simultaneously bulged out and held fast in the dovetail-like wedge positionas indicated in a somewhat exaggerated manner for the sake of clearness in Figure 3.

On considering the pressures exercised by the fibrous material'insertion a on the bars, it will be seen that the fingers d and collar 10 are subjected not only to radial pressure and are firmly held by friction, but are also subjected to the axial pressure of the said insertions whereby the said fingers d and collar 1: are firmly fixed. The hard hammer blow on the nail is elastically taken up by the fibrous material and transmitted to the fingers d and collar is so that the soft plaster is not overstrained by the blow, thus porcelain parts for instance may be safely secured, as by means of a drive screw, without any risk of breaking them by hammer blows.

The plugs according to the present invention can be used when driven in to serve as holding members either by means of a driven-in nail or screw or without the use of such nail or screw. In this latter case, that is when the plug is used to fix a member to a wall or the like without the use of a nail or screw, the hole into which the plug is driven should be made of less depth than the length of the plug, so that on driving in the plug the bars 6 are bulged out similarly to what takes place when a nail is used as shown in Figure 3 and some of the fibrous material overflows laterally from the bars and presses against the walls of the hole.- IVhen the parts fixed by the collar shrink and warp, the plug can be tightened up by a hammer blow on the fibrous material mass, as owing to the blow, the are 0 is first elastically compressed until the collar (or fingers) has again obtained a firm hold, whilst the bars will be held fast elastically in the new position under compression by the frictional pressure ,of the mass of fibrous material, some of which has been pushed to the side and forced out when the -plug was first driven in. It will be seen therefore that when the plug is provided with a collar or fingers and .when it is used in the manner just described, it can be employed in place of an ordinary screw or nail for holding two members together. The time necessary for driving in a screw is therefore saved as the plug may be driven in place to hold the members together by a hammer blow.

It will be seen that a forcibly applied dove-tail-like wedging of the fplug is rendered possible only by means 0 the present invention which involves the joint use of the fingers or bar hold d, the fstem hold 0 and the resilient filling'mass a.

If for instance the fingers d were omitted, the stiffening bars would slide, together with the fibrous material, right down to the bot tom of the hole in the wall. The efficacy of the plug would not then be a fixed factor, but would depend on the depth of the hole and would be practically lndeterminable.

On the other hand, without the stem hold 0 for the fibrous material, the latter would slide between the bars secured tothe ring, down to the bottom of the hole, and press uselessly against the deeper portion of the bottom of the hole and of the walls. Even with a suitable depth of hole, the bars would then be held only bylateral pressure, and the axial (pressure of the fibrous material plu woul act uselessly on the bottom of the ole.

By the counter-bending of the bars I) as shown at k. in Figure 4, the dove-tail-like spreading out of the bars b is assisted as shown in Figure 5'.

Here also, in driving in a nail or the like into the fibrous material, the plug is first resiliently driven in until the collar k is firmly fixed, and then the contracting fibrous material mass a, owing to the increasing pressure during its stemming and compressions, flattens out the counter bent h, whereby teeth, rough edges, or the like which may sion, flattens out the counter bent h, wherebe formed on the bars 6 penerate into the walls of the hole and'firmly secure the plug proper after the fixing.

Instead of the collar shown in Figures 1 to 5, there may be employed an arrangement as shown in Figures 6 and 7, in which a bent-over sheet metal plate Z with a central aperture m is used to cover the end of the plug. It is preferred in such case to make the hole in ,t he plate irre ular in shape as shown in Fig. 6 so that t e resulting teeth of the hole can engage on the one hand with the thread of a screw, and on the other hand accommodate the different thicknesses of nails and therefore give the latter a good hold where they are driven in and at the same time prevent the escape of the mass of, fibrous material. In this connection it will be noted that the above mentioned teeth will bend back as a nail is driven in andthe amount of such bending will depend upon the size of the nail, there being more of such bendingfor larger nails and less for smaller ones.

As shown in Figure 7, this covering cap can also be used in combination with the collar, owing to which the strength of the holding disc is materially increased.

What I claim and desire to secure by Letters Patent of the United States is 1. A wall plug comprising a filling material, and stiffening members arran ed so as to form a framework open at the sides and one end, said filling material being held between and stiffened by said stiffening members and said stiffening members being connected together by a transverse portlon at one end so as to form a stem-hold for the filling material and provided at the other end with retaining means adapted to hold the plug in position when in use.

2. A wall plug comprising a fibrous filling material and stiffeningmembers arranged so :as to form a framework open at the sides and one end, said filling material being held between and stiffened by said stiffening members, and said stiffening members being connected together by a transverse portion at one end so as to form a stem-hold for the filling material and provided at the other end with retaining means adapted to hold the plug in position when in use.

3. A wall plug comprising a fibrous filling material and an approximately U shaped stiffening member between the legs of which the fibrous material .is squeezed, said stiffening member being provided at its open end with retainin members adapted to hold the plug in posit1on when in use.

4. A wall plug as claimed in claim 3 in which the U shaped stiffening member is provided at its open end with fingers and a holding collar for the purpose specified.

5. A wall plug as claimed in claim 3, in which the closed end of the stifi'ening member is formed into a U shaped counterbend or are for the purpose specified.

6. A wall plug comprising a fibrous filling material and an approximately U shaped stiffening member between the legs of which the fibrous material is squeezed, said stiffen ing member having its closed end formed into a U shaped counterbend or are and being provided at its open end with fingers and a holding collar.

FRIEDRICH WALTER KRAUSE. 

